What do TP, TV, TO, TK, TG, TF, TN and TD mean in electrical installation?

P Astronomy, Earth Science P 1 Astronomy P2 Surveying P3 Geophysics P3 1 Earth (Rock) Physics P33 Hydrological Science (Hydrophysics) P35 Space Physics P4 Atmospheric Science (Meteorology) P5 Geology P5 1 Dynamic Geology P52 Paleontology P53 Historical Geology, Stratigraphy P54 Structural Geology P55 Geomechanics P56 Regional Geology P57 Mineralogy P58 Petrology P59 Geochemistry P6 1 Deposit Geology P62 Geology, Mineral Investigation and Exploration P64 Hydrogeology and Engineering Geology [P65] Earthquake Geology [P66] Environmental Geology [P67] Marine Geology P68 Cosmic Geology P69 1 Planetary geology P692 disaster geology P7 oceanography P7 1 marine investigation and observation P72 regional oceanography P73 marine basic science P74 marine resources and development P75 marine engineering [P76] marine environmental science [P77] diving medicine [P79] military oceanography P9 physical geography P90 general theory and method P9 1 mathematical geography [P9 environmental geography [P954] Disaster Geography P96 Natural Resources Science [P97] Geographical Exploration and Discovery P98 Natural Geography Map Q Biological Science Q 1 General Biology Q2 Cell Biology Q3 Genetics Q4 Physiology Q5 Biochemistry Q6 Biophysics Q7 Molecular Biology Q8 1 Bioengineering [Q89] Environmental Biology Q9 1 Paleontology Q93 Microbiology Q94 Botany Q95 Zoology Q96 Entomology Q98 Anthropology R Medicine, Health R 1 Preventive Medicine, Hygiene R2 China Medicine R3 Basic Medicine R4 Clinical Medicine R5 Internal Medicine R6 Surgery R7 1 Obstetrics and Gynecology R72 Pediatrics R73 Oncology R74 Neurology and Psychiatry R75 Dermatology and Sexology R76 Otolaryngology R77 Ophthalmology R78 Stomatology R79 Foreign Ethnic Medicine R8 Special Medicine R9 Pharmacy S Agricultural Science S 1 Agricultural Basic Science S2 Agricultural Engineering S3 Agronomy S4 Plant Protection S5 Crops S6 Gardening S7 Forestry S8 Animal Husbandry, Animal Medicine, Hunting, Silkworm, Bee S9 Aquatic Products, Fisheries T Industrial Technology TB General Industrial Technology TB 1 Engineering Basic Science TB2 Engineering Design and Surveying TB3 Engineering Materials Science TB4 Industrial General Technology and Equipment TB5 Acoustic Engineering TB6 Refrigeration Engineering TB7 Vacuum Technology TB8 Photography Technology TB9 Measurement TD Mining Engineering TD 1 Mine Geology and Survey TD2 Mine Design and Construction TD3 Mine Pressure and Support. TD4 mining machinery TD5 mining transportation and equipment TD6 mining electrician TD7 mine safety and labor protection TD8 mining TD9 beneficiation TD98 mineral resources comprehensive utilization TE oil and gas industry TE0 energy and energy saving TE 1 oil and gas geology and exploration TE2 drilling engineering TE3 oil and gas field development and exploitation TE4 oil and gas field construction engineering TE5 offshore oil and gas field exploration and development TE6 oil, Natural gas processing industry TE8 petroleum, natural gas storage and transportation TE9 petroleum machinery and equipment and automation [TE99] Petroleum, environmental protection and natural gas comprehensive utilization industry TF0 general problems in metallurgical industry TF 1 metallurgical technology TF3 metallurgical machinery, metallurgical production automation TF4 iron and steel metallurgy (ferrous metal smelting) (general) TF5 Ironmaking TF6 Ferroalloy Smelting TF7 Steelmaking TF79 Other Ferrous Metals Smelting TF8 Nonferrous Metals Smelting TG Metallurgy and Metal Technology TG 1 Metallurgy and Heat Treatment TG2 Casting TG3 Metal Pressure Processing TG4 Welding, Metal Cutting and Metal Combination TG5 Metal Cutting and Machine Tool TG7 Tools, Abrasives, Abrasives, Fixtures, Tolerances and technical measurement of molds and hand tools TG8 and mechanical gauge TG9 Bench-fitter technology and assembly technology TH machinery and instrument industry TH 1 1 mechanics (basic theory of mechanical design) TH 12 Mechanical design, calculation and drawing TH 13 Mechanical parts and transmission devices TH 14 Materials for mechanical manufacturing TH/. 6 machinery manufacturing process TH 17 machinery operation and maintenance TH 18 machinery factory (workshop) TH2 lifting machinery and transportation machinery TH3 pump TH4 gas compression and transportation machinery TH6 special machinery and equipment TH7 instruments and meters TJ weapons industry TK energy and electric power industry TL atomic energy technology TM electrician technology TM0 general issues TM 1 Electrician's basic converter and reactor TM5 electrical appliance TM6 power generation, power plant TM7 power transmission and distribution project, TM9 1 independent power supply technology (direct power generation) TM92 electrification, electric energy application TM93 electrical measurement technology and instrument TnRadio electronics, telecommunication technology TN0 general problems TN2 optoelectronics technology, laser technology TN3 semiconductor technology TN4 microelectronics technology, integrated circuit (IC)TN6 electronics.